I found petrol to be around 30 cents cheaper at Costco New Zealand compared to open market.
Costco initially lowered its fuel prices to attract new members, capitalizing on membership fees, which form a crucial part of their business model. Observers noticed that fuel prices at Costco were once significantly cheaper compared to other stations, but they have since aligned more closely with market rates. This pricing strategy might fluctuate, especially around the time when memberships are up for renewal. Some users pointed out that Gull stations, particularly in Onehunga, often offer better deals, especially on diesel, mentioning specific prices and discounts they encountered recently.